Then I try to compile, I get a message that says
"xdiskusage.C: In function `int main(int, char **)':
xdiskusage.C:191: non-lvalue in assignment"
I was unable to find reference to this in any other part of the source, and was unable to access the fltk page to see if somehow this would be solved by upgrading.
So, I commented it out, hopeing it wasn't really necessary.
And it worked. ;-)